Lithium Metal Protection Using Reactive Gas Combinations

Abstract

A passivation process for a lithium metal anode includes subjecting lithium metal to a passivation gas having the following composition: two or more gases selected from the group consisting of CO2, O2, H2O, N2, HC, CO, H, He, F, and SiH4; and optionally, a noble gas. The passivation gas reacts with the lithium metal to form a passivation layer on the lithium metal that is less than ten microns in depth.

What is claimed is: 
     
         1 . A passivation gas for lithium metal, the passivation gas consisting of:
 two or more gases selected from the group consisting of CO 2 , O 2 , H 2 O, N 2 , HC, CO, H, He, F, and SiH 4 .   
     
     
         2 . A passivation gas for lithium metal, the passivation gas consisting of:
 two or more gases selected from the group consisting of CO 2 , O 2 , H 2 O, N 2 , HC, CO, H, He, F, and SiH 4 ; and   a noble gas.   
     
     
         3 . The passivation gas of  claim 2 , wherein the noble gas is argon. 
     
     
         4 . A passivation process for lithium metal, the passivation process comprising:
 subjecting lithium metal to a first passivation gas having a following composition:
 two or more gases selected from the group consisting of CO 2 , O 2 , H 2 O, N 2 , HC, CO, H, He, F, and SiH 4 ; and 
 optionally, a noble gas, 
   wherein the first passivation gas reacts with exposed surfaces of the lithium metal to form a passivation layer on the exposed surfaces that is less than ten microns in depth.   
     
     
         5 . The passivation process of  claim 4 , wherein the passivation layer has a Pilling-Bedworth Ratio of between 1 and 2, inclusive. 
     
     
         6 . The passivation process of  claim 4 , wherein the lithium metal is an anode in an electrochemical cell. 
     
     
         7 . The passivation process of  claim 6 , wherein the electrochemical cell is an all-solid-state battery cell. 
     
     
         8 . The passivation process of  claim 6 , wherein the electrochemical cell is a lithium metal battery cell, wherein the subjecting the lithium metal occurs during cell formation, the passivation process further comprising:
 subsequently subjecting the exposed surfaces of the lithium metal to a second passivation gas during packaging for use, the second passivation gas having the following composition:
 two or more gases selected from the group consisting of CO 2 , O 2 , H 2 O, N 2 , HC, CO, H, He, F, and SiH 4 ; and 
 optionally, a noble gas. 
   
     
     
         9 . The passivation process of  claim 8 , wherein the first passivation gas and the second passivation gas have equal compositions. 
     
     
         10 . The passivation process of  claim 8 , wherein the first passivation gas and the second passivation gas have different compositions. 
     
     
         11 . The passivation process of  claim 8 , wherein subjecting the exposed surfaces of the lithium metal to the second passivation gas produces a second passivation layer that is less than ten microns in thickness. 
     
     
         12 . The passivation process of  claim 8 , wherein subjecting the exposed surfaces of the lithium metal to the second passivation gas modifies a composition of the first passivation layer. 
     
     
         13 . The passivation process of  claim 8 , wherein subjecting the exposed surfaces of the lithium metal to the second passivation gas modifies one or more properties of the first passivation layer.